1. A specialized stinging cell found in jellyfish, sea anemones, and other cnidarians, containing a coiled harpoon-like structure used to capture prey or defend against predators.
Usage: biology; also called cnidocyte or stinging cell

Examples

• Jellyfish use nematocysts to paralyze small fish and plankton.
• The nematocyst fires its barbed filament in milliseconds when triggered.
• Sea anemones rely on nematocysts to capture food particles from the water.
• Each nematocyst contains venom that helps subdue prey.
• The tentacles of a hydra are covered with thousands of nematocysts.
• When you brush against a jellyfish, its nematocysts can cause painful stings.